Cutter head and knife for making wooden gutters



Feb. 8, 1966 c. E. SORENSEN 3,233,642

CUTTER HEAD AND KNIFE FOR MAKING WOODEN GUTTERS Filed July 14, 1964 INVENTOR. (MEL 1 15? S'OPWS'f/V United States Patent M 3,233,642 CUTTER HEAD AND KNIFE FQR MAKING WODDEN GUTTERS Carl Elmer Sorensen, Sorensen Bldg, North Bend, Wash. Filed July 14, 1964, Ser. No. 382,585? 4 Claims. (Cl. 144-218) The present invention relates to a cutter head and paired knives for forming the trough portion of a wooden gutter, such as is used at the eaves of buildings to catch the rain.

Such gutters have commonly had their trough portions formed heretofore by two complemental half-knives, one of which cuts side wall of the trough and such part ofthe bottom thereof as lies at one side of the medial vertical plane, and the other of which cuts the opposite side wall and bottom portion; each such knife presently is separate from but mounted usually adjustably upon a base piece, which in turn is fixedly mounted upon the rotative cutter head block. To complete the cutting, then, four pieces are required at each cutting location, and these must be adjusted carefully and relatively so that they sufficiently coincide in their engagement with the workpiece to cut smoothly and without any intervening ridges, between the portions cut by one knife and the portions cut by the other knife. This is not easy to do and, moreover, the four separate, individually formed pieces constitute an appreciable expense, and require considerable skill to effect their proper adjustment and balance. In addition, each such knife is long, and supported at one end only, hence is rather fragile, especially if worn away by sharpening frequently, or otherwise. Such knives, for this reason, can only be sharpened down to a relatively minor extent and, hence, must replaced fairly often, which in itself is an expense.

It is an object of the present invention to provide a unitary, or one-piece, knife which, in conjunction with a companion one-piece knife, will cut the entire groove portion of the gutter, which is anchored to the cutter head at both its ends, whereby each knife of a pair is strong, and can be sharpened appreciably and adjusted readily so that it is always in correct position, notwithstanding the wearing away of the central portion of the edge (that portion which cuts the bottom of the groove) by such sharpening, and which, when it is eventually worn down appreciably at its initially sharp edge, can be sharpened at its opposite edge and again worn away. This has the effect of lessening the first cost of such a knife and of the cutter head, of which it is a part, and of enabling long usage of the knife, with consequent reduction in expense.

It is also an object so to form such knives that the cutting edges, despite their extent of wear, will always be correctly disposed for balance with respect to a radius through the rotative axis, passing through the knife.

The present invention is shown in illustrative form in the accompanying drawings.

FIGURE 1 is an isometric view of the assembled cutter head showing two knives according to the present invention, incorporated with the rotative block.

FIGURE 2 is an edge view of one of the knives shown in place upon the block and in relation to a workpiece from which a wooden gutter is being formed.

FIGURE 3 is an isometric view of a new knife sharpened at one edge but not worn away by use, such as would constitute a part of the cutter head.

FIGURE 4 is a side elevational view, partly broken away to show the sharpened edge of a new knife, such as that shown in FIGURE 3. FIGURE 5 is a similar view of such a knife sharpened down to an appreciable extent at the initially sharp edge, and FIGURE 6 is a similar view showing such a knife reversed and now sharpened at the opposite edge.

3,233,642 Patented Feb. 8, 1966 FIGURE 7 is a plan view of a knife mounted in position of use upon a block.

The shape of the cutter head block is not highly important in the present invention, and it is shown herein as a more or less square block 3 secured to and rotative with a shaft 30 in the direction shown by the arrow in FIGURE 1. Such a block is provided with seats 31 at equiangularly spaced points (usually diametrically opposite) whereon knives are mounted.

Each knife, according to the present invention, comprises a single piece of steel, or other appropriate metal, indicated by the numeral 1, of U-shape, somewhat narrower than the trough it cuts, and having a depth in excess of the depth of the trough which is to be cut in the gutter indicated in FIGURE 2 by the letter G. This U-shaped piece of metal 1 is sharpened initially along both stern portions of the U-shape, and its bottom portion, at an edge It which is the leading edge in the direction of rotation. The sharpening is to a depth in excess of the depth of the trough which is to be cut in the gutter. This same piece of metal is formed with outstanding flanges 11 at the end portions of the stems of the U, these flanges 11 seating upon a surface 31 of the block 3. Means are provided for securing each knife to the block, which means preferably are in the form of bolts 2 threaded in the block and which pass through apertures 12 in the flanges 11. These apertures 12 may take the form of slots opening from the respective outer ends of the flanges 11. By preference they have a width in excess of the diameter of the bolts 2. The heads 20 of the bolts engage washers 21, and it is possible to shift the knives with respect to the seats 31 forwardly or rearwardly in the direction of rotation, and to cant them at a slight angle to the plane of rotation-see FIGURE 7.

By making each knife narrower than the trough it is to cut, and by canting it to a slight angle from its plane of rotation, the sharpened edge It will cut from approximately the center of the bottom of the U-shape outwardly along the stem at the one side to the full depth of the trough. The edge It at the other side or stem of the U-shape will not out, except at the bottom of the trough. However, by canting the paired, diametrically opposite knife to the same but opposite angle from the plane of rotation, as shown by dash lines in FIGURE 7, its edge It at the stem opposite the cutting stem of the first knife will cut the troughs opposite side wall. The paired knives thus cooperate to cut the entire trough, as do the presently used half-knives, yet each is strong and is anchored at both its ends to the block. Neither has any portion that drags on the troughs side walls, for the arrangement provides clearance for the trailing edge of each knife, as FIGURE 2 shows. Since both knives are identical, they cooperate to cut a smoothly rounded bottom of the trough. If one sharpened stem portion wears, this knife and its paired knife can be reversely canted, and the opposite sharpened stem portion will then take the wear. The enlargement of apertures 12 with respect to the diameter of bolts 2 makes possible such adjustments. It also makes possible slight bodily shifting of the knives ahead with relation to a radius through the axis of rotation, to balance the knives as they wear away from sharpening, thereby avoiding vibration.

Since only one stem of the U-shaped knife cuts at any given setting, it is not essential that initially both stems be sharpened, yet this is preferable, in view of the fact that the paired knives are reversely canted frequently, and sharpening both stems of the U-shape maintains the knife free from imbalance, such as would occur if one stern were sharpened often, and the opposite stem not at all, or infrequently.

Initially, each knife 1 is sharpened at its leading edge at 19, as has already been explained. As the cutting edge wears, from the form shown in FIGURE 4, to the form shown at ltba in FIGURE 5, by sharpening or otherwise, the knife can be advanced slightly so that the cutter head is correctly balanced, as it was initially. Eventually, the knife will wear down to such an extent that it can no longer be resharpened to advantage, or adjusted; and when that occurs, it is possible to remove the knife, to sharpen it at its opposite edge, as indicated at It? in FIGURE 6, and then to reinstall it upon the block 3 in correct relation to the block and to the axis and plane of rotation. Now this edge 10' can be sharpened down from time to time, and along the opposite stems of the U-shape, as was the edge it or 10a, until the metal between the two edges is so thin as to be in danger of cracking, or breaking. The knife can then be discarded, but this ability to wear down the two edges, and each stem of the U-shape at this edge, and then to sharpen the opposite edge to the same extent, while still maintaining it during operation in correct operative position, greatly reduces the cost of the knives in relation to the number of gutters it will form.

It may be explained, in conjunction with FIGURE 2, that such a gutter G is run through a shaping machine, during which operation the paired knives 1 cut the trough portion, and two other cutter heads, at the respectively opposite sides of the path of the workpiece, simultaneously engage and shape the outer and inner side faces of the workpiece, to the shape shown in dot-dash lines in FIGURE 2. The present invention, however, has to do only with the cutting of the trough portion.

1 claim as my invention:

1. A cutter head for forming the trough portion of a wooden gutter, comprising a rotative block and a plurality of one-piece U-shaped knives arranged on said block in diametrically opposite pairs, means to anchor said knives in operative disposition upon the block, each knife having a leading edge which is sharpened substantially throughout the length of at least one stem of the U-shape, and past the bottom thereof, each knife being narrower than the trough to be cut, and the knives of each pair being oppositely canted relative to the plane of 4 rotation, whereby the sharpened stems of the respective knives of a pair lie at opposite sides of that plane and engage the workpiece, to cut away sufiiciently to provide clearance at the same side of that plane for the trailing edge of the paired knife.

2,. A cutter head as in claim 1, wherein the anchoring means is arranged to afford shifting of the individual knives to vary their cant and their disposition.

3. A cutter head for forming the trough portion of a Wooden gutter, comprising a rotative block, a pair of one-piece knives of U-shape with outwardly flanged ends, disposed diametrically oppositely upon said block, the leading edge of each knife being sharpened, throughout at least its portion which engages the workpiece, each flanged end being apertured, and bolts passing through said apertures and into the block to secure the knives in place, said bolts having a shank of less diameter than the width of the apertures, whereby the knifes sharpened edge may be fixed in a selected canted disposition with relation to the plane of rotation, and can be shifted with relation to a given radius through the rotative axis.

4. For use in a rotary cutter head, such as includes a rotative block and generally radially directed knife-anchoring bolts deceived therein, a knife consisting of a single piece of metal formed with parallel legs and a bottom joining portion rounded in U-shape, sharpened and sharpenable repeatedly at at least one edge from the bottom of the U-shape outwardly along at least one leg thereof, end flanges integral with and extending outwardly from the ends of the legs of the U, said end flanges having apertures which are oversize with respect to the shanks of the anchoring bolts, whereby the radially outer end of the sharpened edge can be located substantially within a given radius from the axis of rotation, regardless of the degree of wear due to sharpening, and the knife can be canted about such radius and held thus canted by the anchoring bolts, for clearance of its portion behind the sharpened edge of its leg, during formation of the trough portion of a wooden gutter.

No references cited.

DONALD R. SCI-IRAN, Primary Examiner. 

1. A CUTTER HEAD FOR FORMING THE TROUGH PORTION OF A WOODEN GUTTER, COMPRISING A ROTATIVE BLOCK AND A PLURALITY OF ONE-PIECE U-SHAPED KNIVES ARRANGED ON SAID BLOCK IN DIAMETRICALLY OPPOSITE PAIRS, MEANS TO ANCHOR SAID KNIVES IN OPERATIVE DISPOSITION UPON THE BLOCK, EACH KNIFE HAVING A LEADING EDGE WHICH IS SHARPENED SUBSTANTIALLY THROUGHOUT THE LENGTH OF AT LEAST ONE STEM OF THE U-SHAPED, AND PAST THE BOTTOM THEREOF, EACH KNIFE BEING NARROWER THAN THE TROUGH TO BE CUT, AND THE KNIVES OF EACH PAIR BEING OPPOSITELY CANTED RELATIVE TO THE PLANE OF ROTATION, WHEREBY THE SHARPENED STEMS OF THE RESPECTIVE KNIVES OF A PAIR LIE AT OPPOSITE SIDES OF THAT PLANE AND ENGAGE THE WORKPIECE, TO CUT AWAY SUFFICIENTLY TO PROVIDE CLEARANCE AT THE SAME SIDE OF THAT PLANE FOR THE TRAILING EDGE OF THE PAIRED KNIFE. 